KR100855923B1 - Adhesive optical film - Google Patents

Abstract

The pressure-sensitive adhesive layer included in the pressure-sensitive adhesive optical film forms a portion disposed inward from the edge line of the optical film.

Description

Adhesive optical film {ADHESIVE OPTICAL FILM}

The present invention relates to an adhesive-type optical film having an adhesive layer laminated on one or both sides of an optical film. In addition, the present invention is an adhesive optical film including at least one layer selected from the adhesive optical film and the release film (release film), the optical layer, the optical film and the pressure-sensitive adhesive layer, and the liquid crystal using the adhesive optical film A display device (LCD), an electroluminescent display (ELD), a plasma display panel (PDP) and a field emission display (FED).

Due to the picture forming system adopted in the liquid crystal display device, it is inevitable for the liquid crystal display device to arrange a polarizing plate on both sides of the glass substrate which constitutes the outermost face of the liquid-crystal panel. The polarizing plate is generally adhered to the outermost surface of the liquid crystal panel. In addition, in order to further improve the display quality, the use of various optical members in addition to the polarizing plate on the outermost surface of the liquid crystal panel has increased considerably. For example, a retardation plate for preventing coloring, a viewing angle enlarging film for widening the viewing angle, and a brightness enhancement film for enhancing the contrast are used. These films are collectively referred to as optical films.

When the optical film is attached, an adhesive is generally used to prevent the loss due to reflection of light at the interface. In addition, the adhesive can be fixed in an instant, and the adhesive is provided in advance as an adhesive layer on one or both sides because of the advantage of not having to dry the optical film for fixing. That is, a pressure-sensitive adhesive optical film is generally used to adhere the optical film to a liquid crystal panel or the like.

When the adhesive optical film is transported, transported or handled, for example, in a manufacturing and processing work line, a defect, particularly at the edges of the adhesive optical film, may cause the adhesive to adhere to the end of the optical film and some kind of material. The phenomenon of falling into the chip state due to contact with (hereinafter "adhesive chip") occurs in the outer unprotected side of the pressure-sensitive adhesive layer. There is also a case where the peeled off adhesive contaminates the surface of the optical film (hereinafter, “adhesive contamination”). Once an adhesive chip is formed, hard adhesion becomes impossible and, to make matters worse, the chip portion forms an air layer and has a different refractive index and direction of vibration than the other portions, causing a defective display. Likewise, the adhesive contamination also causes a defective display.

In order to prevent such adhesive chips and adhesive contamination, a method of adhering powder to the edge of the adhesive layer (see JP 2001-272539 A), which forms a non-tack layer on the edge of the adhesive layer through spray coating The method (see JP 2000-258627 A), or the method of forming the side surface of the adhesive optical film into a protruding-depressed repeating structure (JP 2001-033623 A) has been used to date. However, these methods involve contamination by foreign substances in powder or sprayed coatings or require complex processes. Therefore, a simpler and easier method is required.

The present invention has a pressure-sensitive adhesive layer which has a pressure-sensitive adhesive layer laminated on one or both sides of the optical film, and which hardly causes pressure-sensitive adhesive chips and pressure-sensitive adhesive contamination during transportation and handling, or in a manufacturing and processing-working line. The aim is to provide a simpler and easier. Moreover, an object of this invention is to provide the method of manufacturing the said adhesive optical film, and the image display apparatus using the said adhesive optical film.

According to the present invention, there is provided a pressure-sensitive adhesive optical film having one or both sides of an optical film, that is, at least one optical film surface, in which the pressure-sensitive adhesive layer is located inward from the optical film edge. In other words, the adhesive optical film provided by the present invention is an adhesive optical film including an optical film and a pressure-sensitive adhesive layer laminated on at least one side of the optical film, and at least a part of an edge of the pressure-sensitive adhesive layer in the optical film. Is located inward from the optical film edge. The edge of the pressure-sensitive adhesive layer located inward from the optical film edge is referred to as an "inside edge".

It is possible to laminate at least one layer selected from a release film, an optical layer, an optical film, and an adhesive layer to the pressure-sensitive adhesive optical film. The adhesive optical film of the present invention can be used in an image display device such as LCD, ELD or FED.

The present invention also provides a method for producing a pressure-sensitive adhesive optical film, which pressurizes both sides of the pressure-sensitive adhesive layer to extract a portion of the pressure-sensitive adhesive layer from the side edges of the optical film, and in this state the side of the pressure-sensitive adhesive layer Scraping off or cutting off and removing the pressure on the pressure sensitive adhesive layer.

According to the present invention, the pressure-sensitive adhesive layer of the pressure-sensitive optical film having the pressure-sensitive adhesive layer laminated on one or both sides of the optical film is located inward from the edge of the optical film, and thus during the transport and handling or the manufacturing and processing-working line In addition to the contamination caused by the adhesive pushed out from the edge (adhesive contamination), it is possible to easily and simply obtain a pressure-sensitive adhesive optical film which does not easily generate the adhesive chip.

Making the adhesive optical film according to the present invention is carried out by forming an adhesive layer on one or both sides of the optical film, these adhesive optical films are used in the form of stacking on top of each other in two or more layers, or It can be used as a pressure-sensitive adhesive optical film laminated on the release film, optical film or optical layer. In addition, it is not desirable to place or transport the optical film with the adhesive layer exposed and in direct contact with an air interface, so that a release film layer is placed on the adhesive optical film for protection before use. It is desirable to provide.

According to the present invention, it is possible to produce a pressure-sensitive adhesive optical film which does not cause pressure-sensitive adhesive chips and pressure-sensitive adhesive in the process of carrying or handling with the pressure-sensitive adhesive layer on one side or both sides of the optical film, or the manufacturing and processing work line.

A basic example of the adhesive optical film is shown in FIGS. 1A and 1B. Each of these adhesive optical films 4 is made by laminating the adhesive layer 2 on one or both surfaces of the optical film 1, that is, at least one surface of the optical film. As shown in Figs. 3A and 3B, the adhesive optical film 4 can be stacked in two or more layers. In addition, a layer 3 selected from a release film, an optical layer, an optical film and an adhesive layer may be laminated thereto.

As an example of the optical film, an optical element supported by a substrate such as a film and used to form an image display device may be mentioned. Specific examples of such optical elements include polarizers, polarization conversion elements, reflectors and translucent reflectors, retardation plates (including 1/2 and quarter wave plates (λ plates)), visual There are a viewing angle compensating film, a brightness enhancement film and a protective film.

The optical layer is formed on the optical film directly or through a pressure-sensitive adhesive layer or a pressure-sensitive adhesive layer and has an optical element used to form an image display device. Various types of directional liquid crystal layers having properties for controlling visual compensation characteristics and birefringence characteristics, easy-bonding treated layers, hard coat layers, and anti-reflection layers Various types of surface-treated layers such as reflection layers, anti-sticking layers, diffusion layers and anti-glare layers are included in specific examples of the optical layers. do.

Examples of release films include thin layers of synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate films, rubber sheets, paper, cloth, nonwoven fabrics, nets, foamed sheets, thin metal films, and laminates thereof do. In addition, in order to improve the separation from the pressure-sensitive adhesive layer, it is preferable to perform a treatment such as silicon treatment, long-chain alkyl treatment or fluoric treatment on the surface of the release film as necessary. Do.

The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive optical film of the present invention is not particularly limited as long as it does not adversely affect the required optical properties. A composition obtained by mixing a silane coupling agent and an acrylic polymer having an acrylic oligomer and a photopolymerization initiator are added to the acrylic polymer to irradiate ultraviolet (UV) light ( irradiated) compositions are included in these examples.

The acrylic polymer is obtained by copolymerizing a monomer having a functional group capable of reacting with a main monomer alkyl (meth) acrylate and a multifunctional compound. You may lose. It is also possible to introduce carboxyl groups into the acrylic polymer. The weight average molecular weight of the acrylic polymer is 400,000 or more, preferably 1,000,000 to 2,000,000. Incidentally, the term "(meth) acrylate" means an acrylate, methacrylate or acrylate-methacrylate mixture, and the term "(meth)" is the same as described above Has meaning.

The average number of carbon atoms in the alkyl group of the alkyl (meth) acrylates in which the acrylic polymer makes up the main skeleton is 1 to 12. Examples of such alkyl (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and isooctyl (meth) acrylate ( isooctyl (meth) acrylate). These monomers may be used alone or in combination.

Examples of the monomer unit having a functional group capable of reacting with the multifunctional mixture copolymerizable with the acrylic polymer include a monomer including a carboxyl group, a monomer including a hydroxy group, and a monomer including an epoxy group. Monomers containing a carboxyl group are, for example, acrylic acid, methylacrylic acid, fumaric acid, maleic acid and itaconic acid. Examples of the monomer containing a hydroxy group include 2-hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, and hydroxyhexyl ( Hydroxyhexyl (meth) acrylate and N-methylol (meth) acrylamide. One example of a monomer comprising an epoxy group is glycidyl (meth) acrylate. Among them, it is preferable in the present invention to use a monomer containing a carboxyl group.

A monomer unit having a nitrogen component may be further introduced into the acrylic polymer. Examples of monomers containing a nitrogen component include (meth) acrylamide, nitrogen, nitrogen-dimethyl (meth) acrylamide (N, N-dimethyl (meth) acrylamide), nitrogen, nitrogen-diethyl (meth) acrylamide (N N-diethyl (meth) acrylamide, (meth) acryloylmorpholine, (meth) acetonitrile, vinyl pyrrolidone, nitrogen-cyclohexyl Maleimide (N-cyclohexylmaleimide), itaconimide and nitrogen, nitrogen-dimethylaminoethyl (meth) acrylamide (N, N-dimethylaminoethyl (meth) acrylamide). In addition to these monomers, vinyl acetate, styrene, and the like can be used for the acrylic polymer to the extent that the adhesive properties are not impaired. The monomers may be used alone or in combination of two or more.

The proportion of the monomer unit in the acrylic polymer is not particularly limited, but the ratio is preferably in terms of weight to 100 weight of alkyl (meth) acrylate in terms of durability. About 0.1 to 12, more preferably 0.5 to 10 by weight.

Using a radical polymerization method including a bulk polymerization method, a solution polymerization method and a suspension polymerization method or, for example, an infrared light. The acrylic polymer may be prepared by a method appropriately selected from various general methods such as a photo polymerization method. In the radical polymerization process, various general azo-type and perozide-type initiators can be used, the reaction temperature is 50 ° C. to 85 ° C., and the reaction time is 1 to 10 hours. Of these preparation methods, the solution polymerization method is preferred over other methods, and polar solvents such as ethyl acetate and toluene are generally used as solvents for acrylic polymers. The concentration of such solutions is generally 20 to 80% by weight. It is also desirable to adopt a method for producing the acrylic polymer in combination with UV polymerization using a photo-polymerization initiator comprising benzophenone.

In the present invention, an acrylic polymer having a weight average molecular weight of 400,000 or more is used, correspondingly well compatible with the acrylic polymer, and having an weight average molecular weight of preferably 800 to 50,000, more preferably 1,000 to 10,000 acrylic oligomers. ) Can be used. The amount of the oligomer used when the weight of the acrylic polymer is 100 is 1 to 300, preferably 10 to 250, more preferably 20 to 200 by weight. When the amount of the acrylic oligomer used is less than 1 in weight, the adhesion is so strong that a satisfactory reworking property cannot be obtained, whereas foaming is used when the acrylic oligomer is used by 70 or more by weight. ), The problem of delamination is likely to occur under high temperature and high humidity conditions. The glass transition temperature of the acrylic oligomer is -5 ° C to -100 ° C, preferably -15 ° C to -70 ° C. Such oligomers change adhesion characteristics through surface contamination of glass substrates, such as adhesives, and cause bleeding of low molecular weight urea, so that the weight average molecular weight of less than 800 is undesirable. On the other hand, when the glass transition temperature is higher than −5 ° C. or when the weight average diamagnetic weight exceeds 50,000, the adhesive force becomes strong and satisfactory reworkability cannot be obtained. In the present invention, the molecular weight distribution of the acrylic oligomer is preferably 1 to 2, more preferably 1 to 1.7. It is not desirable that the molecular weight distribution be wider than 2 because of changes in the stickiness caused by contamination of the glass substrate surface such as the adhesive face and leakage of low molecular weight elements.

The oligomers in which each main skeleton consists of the same (meth) acrylate monomer units as in the acrylic monomers are the acrylic oligomers usable here, and as mentioned above the acrylic oligomers are identical The comonomer unit is included in copolymerized form.

The acrylic oligomer can be prepared according to various general methods. One example is a method of preparing the acrylic oligomer by living radical polymerization using a specific polymerization activator and a radical polymerization initiator. By using the above method, it is possible to easily prepare an acrylic oligomer having a narrow molecular weight distribution in the presence of a small amount of solvent or without a solvent without problems such as polymerization temperature control.

Transition metals and their ligands are used as the radical polymerization initiator. Cu, Ru, Fe, Rh, V and Ni are included in the examples of such transition metals, and these metals are generally used in the form of halides (chlorides, bromide, etc.). The ligand forms a coordinate complex around the transition metal, and a bipyridine derivative, a mercaptane derivative, and a trifluorate derivative form the coordination complex. This is a suitable example. From a rate of polymerization and the stability in a surface coordinated complex of transition metal and ligand copper-two feet limiter Dean complex (Cu ^{1 +} -bipyridine complex) is preferable than the other.

Compounds suitable as such radical polymerization initiators are ester or styrene derivatives having halogen in their α-positions, in particular 2-bromo (or chloro) propionic acid derivatives and chlorine Chlorinated (or brominated) 1-phenyl derivative. Examples of such derivatives include methyl 2-bromo (or chloro) propionate, ethyl 2-bromo (or chloro) propionate (ethyl 2-bromo (or chloro) ) propionate), methyl 2-bromo (or chloro) methylpropionate (methyl 2-bromo (or chloro) methylpropionate), ethyl 2-bromo (or chloro) methylpropionate (ethyl 2-bromo (or chloro) ) methylpropionate) and 1-phenylethyl chloride (or bromide).

In living radical polymerization, the radical polymerization initiator is preferably used in a molar ratio of 0.01 to 5% with respect to the polymerization component. The transition metal in the halogenated form is generally used in an amount of 0.01 to 1 mole per mole of the radical polymerization initiator. In addition, the ligand of the transition metal is generally used in the form of 1 to 3 moles per mole of the transition metal (in the form of halogenation or the like). The use of such proportions of radical polymerization initiators and polymerization activators can produce good reaction results in living radical polymerization, the weight average molecular weight of the oligomers produced, and the like.

It is possible to proceed with the living radical polymerization without using any solvent, or it is also possible to proceed with the living radical polymerization in the presence of a solvent such as butyl acetate, toluene or xylene. When a solvent is used, it is preferable to control the amount of the solvent used so that the concentration of the solvent is 50% by weight or less at the end of the polymerization in order to prevent a decrease in the polymerization rate. Regarding the polymerization conditions, the polymerization temperature is 50 to 130 ° C., and the polymerization time is 1 to 24 hours in consideration of the polymerization rate and deactivation of the catalyst used.

The oligomers formed by this method consist of homopolymers, random copolymers or block copolymers, and the oligomers are polymers having a narrow molecular weight distribution (low number average molecular weight). ratio of weight average molecular weight to weight). Incidentally, a random copolymer may be formed by continuous living radical polymerization of two or more kinds of monomers.

The number average molecular weight is a value measured by gel permeation chromatography (GPC) and used to calculate polystyrene. The number average molecular weight (Mn) of the oligomer is expressed by Mn (calculated value) = [(molecular weight of monomer) x (molar ratio of monomer)] / (molar ratio of polymerization initiator). Therefore, the number average molecular weight of the oligomer can be adjusted by controlling the ratio of the amount of the prepared monomer to the amount of the polymerization initiator produced, and the intended oligomer can be easily obtained.

With respect to the photopolymerization initiator, various types of photopolymerization initiators can be used without particular limitation. Examples of such initiators include Irgacure 907, Irgacure 184, Irgacure 651 and Irgacure 369 produced by Ciba Specialty Chemicals. . In general, it is appropriate to add the photopolymerization initiator by about 0.5 to about 30 by weight when the weight of the polymerization component is 100.

In the pressure-sensitive adhesive component, a multifunctional compound may be used. The multifunctional compound is, for example, an organic cross-linking agent or a multifunctional metal chelate. Epoxy type crosslinking agents, cross-linking agents of isocyanate type and imine type cross-linking agents are included in the examples of organic crosslinking agents. The multifunctional metal chelate is a compound formed by bonding a polyvalent metal atom and an organic compound through covalent or coordinating bonds. Examples of such polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, SN and Ti There is. As an example of the atom of the organic compound which forms a covalent bond or coordination bond, an oxygen atom can be mentioned. Examples of such organic compounds include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds and ketone compounds. In the present invention, it is preferable to use a cross-linking agent of isocyanate type.

As long as the crosslinking agent is a compound having two or more isocyanate groups per molecule, there is no particular limitation on the isocyanate crosslinking agent used in the pressure-sensitive adhesive component. Examples of compounds usable as isocyanate type crosslinking agents include tolylene diisocyanate, 4-4'-diphenylmethane diisocyanate, and hexamethylene diisocyanate. Xylylene diisocyanate, naphthylene-1,5-diisocyanate, o-toluidine isocyanate, isophorone diisocyanate, and Isocyanates, such as triphenylmethane triisocyanate, and polyhydric alcohol compounds, and polyisocyanates produced by condensation of isocyanates. The trade names of these isocyanates in the market are Coronate L, Coronate HL, Coronate 2030, produced by Nippon Polyurethane Industry Co., Ltd., Coronate 2031, Millionate MR and Millionate MTL; Takenate D-102, Takenate D-110N, Takenate D-200 and Takenate produced by Takeda Pharmaceutical Company Limited Takenate D-202; Desmodule L, Desmodule IL, Desmodule N, and Desmodule HL produced by Sumitomo Bayer Urethane Co., Ltd. have. In addition, these products can be used alone or in combination of two or more thereof. There is no particular limitation on the mixing ratio of the acrylic polymer to the isocyanate crosslinking agent, but the isocyanate crosslinking agent is about 0.05 to 6, preferably 0.1 to 3 by weight, based on 100 (wt) of the acrylic polymer. Mix in proportions.

In the above pressure-sensitive adhesive composition, glass fiber, glass beads, metal powders and other inorganic powders, pigments, coloring agents, bulking agents, antioxidants, ultraviolet absorbers (if necessary) Fillers, plasticizers, tackifiers and silane coupling agents made of ultraviolet absorbents may further be used. In addition, various additives may be used as appropriate within the scope of the present invention. In addition, the pressure-sensitive adhesive composition may include fine particles, and may be formed of an pressure-sensitive adhesive layer exhibiting light diffusing property. In the present invention, the addition of the silane coupling agent is suitable for adjusting the adhesive strength.

Examples of silane coupling agents that can be used for this purpose include, but are not limited to, vinyltriethoxysilane, vinyltri (beta-methoxyethoxy) silane, gamma-methacryl Γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-cidoxydoxypropyltriethoxy Silane (γ-glycidoxypropyltriethoxysilane), beta- (3,4-ethoxycyclohexyl) ethyltrimethoxysilane (β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane), gamma-chloropropylmethoxysilane (γ- chloropropylmethoxysilane, vinyltrichlorosilane, gamma-mercaptoprophiltrimethoxysilane, gamma-aminopropyltriethoxysilane, and vagina Bovine-beta (aminoethyl)-[gamma] -aminopropyltrimethoxysilane (N- [beta] (aminoethyl)-[gamma] -aminopropyltrimethoxysilane). These silanes may be used alone or in combination of two or more thereof. In the present invention, it is generally necessary to add the silane coupling agent in a ratio of 0.01 to 5.0 by weight, preferably 0.03 to 2.0 by weight, relative to 100 weight of the acrylic polymer (solid state).

The method for forming the pressure-sensitive adhesive layer is not particularly limited, but for example, a pressure-sensitive adhesive layer on a release film or a method of coating the pressure-sensitive adhesive composition (in solution) on one or both sides of the optical film and drying the coated composition. Is formed by application, the pressure-sensitive adhesive composition is dried, the composition is irradiated with UV or the like, a release film is placed on one or both sides of the optical film through the pressure-sensitive adhesive layer, and The pressure-sensitive adhesive layer is formed using a method of transferring the pressure-sensitive adhesive layer to the optical film by peeling the release film from the pressure-sensitive adhesive layer. In this method, if necessary, an appropriate amount of UV may be irradiated to the pressure-sensitive adhesive composition to be applied to the optical film or the release film.

The drying temperature of the pressure-sensitive adhesive layer is appropriately adjusted according to the type of pressure-sensitive adhesive composition, generally 70 to 150 ℃. The drying time is preferably 1 to 5 minutes. There is no particular limitation on the thickness (after drying) of the pressure-sensitive adhesive layer, but it is preferably 5 to 50 μm. When the thickness is thinner than 5 μm, the pressure-sensitive adhesive layer is easy to peel off, causing a problem of durability. On the other hand, since the pressure-sensitive adhesive layer has an excessively high adhesive strength, it is not preferable that the pressure-sensitive adhesive layer has a thickness of more than 50 μm when applied to an optical film designed in consideration of re-peelability. However, when applying a polymerization method using UV irradiation, it is possible to form an adhesive layer having a thickness of 100 μm to 1 mm, and it is preferable to adjust the thickness in the range of 200 to 800 μm. As described above, forming a relatively thick pressure-sensitive adhesive layer improves the shock-absorbing ability, so that the pressure-sensitive adhesive layer can absorb the impact caused by a collision or the like when it hits another optical film such as a panel, thus preventing the effect of fracture. Is improved.

In the present invention, at least part of the edge of the pressure-sensitive adhesive layer is located inward from the edge of the optical film laminated to the pressure-sensitive adhesive layer (such a portion of the pressure-sensitive adhesive layer is referred to as an "inner edge"). Generally in such a state, the said adhesive layer has a cross-sectional shape shown, for example in FIG. 1A. However, as shown in Figs. 2A to 2D, the pressure-sensitive adhesive layer has a portion of the edge of the pressure-sensitive adhesive layer 2 as seen in cross section until the edge of the optical film 1 or the layer 3 is near. It can be shaped to have an elongated cross-sectional shape, ie an outwardly extending cross-sectional profile. The edge of the pressure-sensitive adhesive layer in contact with the optical film (1) or the layer (3) or a portion having an outer elongate shape, unless it protrudes from the edge line, the edge of the optical film (1) or the layer (3) May be present nearby. In other words, the portion having the outer elongated shape is sufficient to be positioned by 0 µm or more inward from the edge of the optical film 1. In addition, it is preferable that the part having an outer elongate shape is located 5 to 50 μm inward from the edge line of the optical film 1, because the pressure-sensitive adhesive layer having such a cross-sectional shape is made with respect to an adhesive chip. This is because they have greater tolerance. In Fig. 2A, a concave end face 5 having a concave cross-sectional shape is formed. 2B and 2C, slant end faces 6, 7 with slant cross-sectional profiles are formed. 1A, 2A or 2C (the inclined end face 7 of the pressure sensitive adhesive layer has a cross-sectional shape extending outward from the layer 3 side toward the optical film 1 side). It is preferable to form the pressure-sensitive adhesive layer having a cross-sectional shape shown in the). In addition, as shown in Figure 3a or 3b, when the pressure-sensitive adhesive optical film has two or more pressure-sensitive adhesive layer, the shape of the portion located inward from the edge line of the optical film, and whether or not the presence of the portion is determined Can be.

It is effective that the edge of the pressure-sensitive adhesive layer located inward from the edge of the optical film is formed at least in part of the edge of the optical film, but the pressure-sensitive adhesive layer inward from the edge of the optical film at the entire edge of the pressure-sensitive adhesive layer. The more edges of, the higher the effect. More specifically, it is preferable that the inner edge of the pressure-sensitive adhesive layer is formed at least half of the entire circumference of the optical film, preferably at least 3/4, more preferably all over the perimeter, depending on the shape of the optical film. Do. In addition, the cross-sectional shape of the edge of the pressure-sensitive adhesive layer located inward from the edge of the optical film may be different from one edge and the other edge as shown in Figure 2d. In the pressure-sensitive adhesive optical film of FIG. 2D, the convex end face 8 having a convex cross-sectional shape is formed in addition to the concave end face 5.

An example of a method of providing an edge of an adhesive layer located inward from an edge of an optical film includes forming an adhesive layer in an area located therein at an appropriate distance from the edge of the stamped optical film upon coating or delivery. And a method (cut-half method) for removing only a portion of the pressure-sensitive adhesive layer after coating or transferring the pressure-sensitive adhesive layer, while having an optical film laminated on both sides of the pressure-sensitive adhesive layer. In the pressure-sensitive adhesive optical film, the optical film or the release film having the pressure-sensitive adhesive layer interposed therebetween may have a different size, so as shown in FIG. 1B, the pressure-sensitive adhesive layer is more effective than the optical film having the pressure-sensitive adhesive layer. Can be formed on the surface of an optical film or a release film having a small area, on which a larger optical film It may cheungdoel. When using a smaller area of the release film, the structure shown in Figure 1a can be removed, and the release film from the pressure-sensitive adhesive layer formed by laminating the optical film is greater than the size in the pressure-sensitive adhesive layer.

When the distance is too long with respect to the distance between the edge of the optical film and the edge of the edge of the pressure-sensitive adhesive layer located inward from the edge of the optical film (the longest gap), for example, a liquid crystal having a narrow width frame, which is recently common When the pressure-sensitive adhesive layer is formed on the panel, a problem related to the display occurs, whereas when the distance is too short, it becomes difficult to achieve the pressure-sensitive adhesive chip and the anti-fouling effect achieved in the present invention. Therefore, it is necessary to adjust to a suitable distance according to the purpose of the end use. In general, the distance is preferably 10 to 300 μm, more preferably 20 to 250 μm, even more preferably 50 to 150 μm.

In the case of a pressure-sensitive adhesive optical film having an optical film laminated on both sides of the pressure-sensitive adhesive layer, the pressure-sensitive adhesive optical film having the pressure-sensitive adhesive layer inserted between the two optical films from the both sides is pressed (fixing one side and pressing only the opposite side). A portion of the pressure-sensitive adhesive layer is discharged from the side surface of the optical film, and the end portion of the pressure-sensitive adhesive layer is released by scraping or cutting off the pushed-out portion of the pressure-sensitive adhesive layer and releasing the pressure applied to the pressure-sensitive adhesive layer. There is a way to get inward from the film edge. Since the pressure-sensitive adhesive layer is more easily returned to its original shape when releasing pressure, the pressure-sensitive adhesive suitably used in the case of applying such a method is a somewhat elastic pressure-sensitive adhesive. Regarding the elasticity modulus of the pressure-sensitive adhesive used in this case, the storage modulus determined from the dynamic viscoelasticity is preferably 1.0 × 10 ⁴ to 1.0 × 10 ⁷ Pa, more preferably at 25 ° C. For example, 1.0 × 10 ⁴ to 1.0 × 10 ⁶ Pa. Alternatively, the loss modulus determined from the kinematic viscoelasticity is preferably 1.0 × 10 ² to 1.0 × 10 ⁷ Pa, more preferably 1.0 × 10 ³ to 1.0 × 10 ⁵ Pa at 25 ° C. To determine this value, a measurement is carried out using a viscoelastic measuring instrument (ARES, manufactured by Rheometric Scientific FE Inc.) in the temperature range of -50 ° C to 150 ° C, and the value measured at 25 ° C is taken.

As another method for entering the end of the pressure-sensitive adhesive layer inward from the edge line of the optical film, the pressure-sensitive adhesive layer pulls one side or both sides of the pressure-sensitive adhesive optical film therebetween outward in the thickness direction of the pressure-sensitive adhesive layer. It is possible to adopt the method, and as the pressure-sensitive adhesive used in this case, a pressure-sensitive adhesive that tends to exhibit plastic deformation when a force is applied is preferable. Thus, a somewhat viscous adhesive is preferably used.

As mentioned above, in the case where the pressure-sensitive adhesive optical film having the optical film laminated on both sides of the pressure-sensitive adhesive layer is pressed and the pressure-sensitive adhesive layer is scraped off or cut out, the pressure-sensitive adhesive layer is combined with the optical film in terms of productivity. It is desirable to mow or cut together. In the example of the method of adjusting the distance from the edge of the said optical film to the edge of the said adhesive layer located in the inside of the said optical film, when adopting the method of cutting or cutting the said adhesive optical film after pressurization, the said adhesive layer A method of controlling the amount of the (cut off) pressure-sensitive adhesive layer to be cut off when cutting out or cutting off the extruded portion of the method, a method of controlling the pressure applied to the pressure-sensitive adhesive layer and a method of adjusting the elastic modulus of the pressure-sensitive adhesive layer.

In the example of the method for forming the pressure-sensitive adhesive layer having a cross-sectional shape shown in Figure 2c, a method of cutting half of the edge of the pressure-sensitive adhesive layer obliquely in the cross-section, as previously mentioned, pressurizing the pressure-sensitive adhesive optical film and in cross-section diagonally A method of scraping off the pressure-sensitive adhesive layer (so that the pressure-sensitive adhesive layer has a cross-sectional shape as shown in FIG. 2C after the pressure is released), and a pressure-sensitive adhesive layer is formed on the optical film so as to have a protrusion in the central region of the optical film. And laminating a release film or an optical film to the pressure-sensitive adhesive layer. In addition, such a cross-sectional shape can be formed when the two films with the adhesive layer sandwiched therebetween have very different interfacial properties.

Additionally, for example, salicylate compounds, benzophenol compounds, benzotriazole compounds, cyanoacrylate compounds and nickel complex compounds Ultraviolet absorbency may be added to the optical film and the pressure-sensitive adhesive layer used in the present invention according to a method of treating the optical film using an ultraviolet absorbent such as).

The optical film is an optical film used to form an image display device, and there is no particular limitation on such use. Examples of such uses include polarizing plates, retardation plates, elliptical polarizing plates, visual compensation films and brightness increasing films.

The polarizing plate generally used like the optical film is a polarizing plate having a transparent protective film on one side or both sides.

The polarizer used herein is not particularly limited and may be various kinds. Examples of such polarizers include polyvinyl alcohol films, partially formalized polyvinyl alcohols by absorbing dichromatic substances, such as iodine or dichromatic dyes. hydrophilic polymer films such as films and partially saponified ethylene-vinyl acetate copolymers are made, and the films are then uniaxially drawn to dehydrate the products of polyvinyl alcohol. And films for making and making oriented polyene films, such as dehydrochlorination products of polyvinyl chloride. Among them, polarizers containing a dichroic substance such as polyvinyl alcohol film and iodine are preferable. There is no particular limitation on the thickness of such polarizers but is generally 5 to 80 μm.

Iodine can be used to make polyvinyl alcohol film polarizers by dyeing polyalcohol vinyl by dipping in aqueous iodine solution and drawing the dyed film 3 to 7 times its original length. The polyvinyl alcohol film may include boric acid, zinc sulfate, zinc chloride, and the like, if necessary, and may be dipped in an aqueous solution such as potassium iodide. Prior to dyeing, the polyvinyl alcohol film may be further washed by dipping into water as necessary. By washing the polyvinyl alcohol film with water, it is possible to wash off the coloring agents and blocking inhibitors on the surface of the polyvinyl alcohol film, and also cause the polyvinyl alcohol film to swell and be uneven, such as uneven dyeing. It will have the effect of preventing. The stretching may be done after or during staining with iodine or may be dyed with iodine after stretching. Alternatively, the stretching may be performed in an aqueous solution of boric acid or potassium iodide, or in a water bath.

As a material for forming the transparent protective film provided on one or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, imperviousness to water, isotropy and the like is suitable. Examples of such materials include polymers of polyester type such as polyethylene terephthalate and polyethylene naphthalate; Cellulose type polymers such as diacetyl cellulose and triacetyl cellulose; Acrylic polymers such as polymethyl methacrylate; Styrene polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin); And polycarbonate type polymers. Polyolefin-type polymers such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure and ethylene-propylene copolymers; Vinyl chloride polymers; Amide polymers including nylon and aromatic polyamides; Imide polymers; Sulfone polymers; Polyethersulfone polymer; Polyether ether ketone polymers; Polyphenylene sulfide polymers; Alcohol vinyl polymers; Vinylidene chloride polymer; Butyral vinyl polymer; Arylate polymer; Polyoxyethylene polymers; Epoxy polymers; And mixtures of two or more of the polymers may be given as other examples of polymers forming the transparent protective film. The transparent protective film may also be formed as an ultraviolet-curable resin or thermosetting cured layer of acrylic, urethane, acrylic urethane, epoxy or silicone type. Among these, the polymer containing the hydroxyl group which has reactivity with an isocyanate crosslinking agent is preferable, More preferably, it is a cellulose type polymer. The thickness of the transparent protective film is not particularly limited, but is generally 500 μm or less, preferably 1 to 300 μm, more preferably 5 to 200 μm.

As an example of a transparent protective film, a film (A) of a resin component containing a thermosetting resin having an imido group substituted and / or unsubstituted in a side chain and / or substituted in the side ring and / Or a thermosetting resin (B) having an unsubstituted phenyl group and a nitrile group, and in particular an alternating copolymer of acrylonitrile-styrene copolymer, nitrogen-methylmaleimide and isobutene And the polymer film described in Japanese Patent Application No. 2001-343529 A (WO 01/37007), such as a film of a resin component containing. Hybrid extrusion products of such resin components can be used as the film.

The thickness of such a transparent protective film is not particularly limited, but is generally 500 μm or less, preferably 1 to 300 μm, more preferably 5 to 200 μm. In addition, it is preferable that the surface of the protective film saponify with alkali or the like from the viewpoint of polarization characteristics and durability.

It is also preferred that the transparent protective film have as low coloring as possible. Therefore, it is preferable to use a transparent protective film having a retardation value in the film thickness direction of -90 nm to +75 nm, wherein the retardation value is Rth = [(nx + ny) / 2-nz] · d (nx and ny are in-plane main refractive index, nz is the refractive index in the thickness direction, d is the layer thickness). By the use of a transparent protective film having a retardation value Rth of -90 nm to +75 nm in the thickness direction, the coloring (optical coloring) of the polarizing plate due to the transparent protective film can be almost solved. The retardation value Rth in the thickness direction is preferably -80 to +60 nm, more preferably -70 nm to +45 nm.

One side of the transparent protective film to which the polarizing plate is not attached (where the coating layer is not provided) may have a hard coating layer, and may be treated for anti-reflective treatment, sticking prevention, diffusion or antiglare. Can be

For the purpose of including scratch protection on the surface of the polarizing plate, the hard coating treatment may be performed, and, for example, may be formed according to a method of making a cured film from a suitable ultraviolet curable resin of acrylic or silicon type having excellent hardness. And a sliding property is added to the surface of the transparent protective film. The anti-reflective treatment is performed to prevent the reflection of extraneous light from the surface of the polarizing plate, for example, by forming an anti-reflective coating according to a general method. In order to prevent adhesion to an adjacent layer, the said anti-sticking process is performed.

And the anti-glare treatment, for example, to prevent visual recognition of light transmitted by the polarizer from being suppressed by reflection of external light from the surface of the polarizer, and sandblasting treatment. Or finely uneven structure on the surface of the transparent protective film according to a suitable method such as a surface roughening method using an embossing treatment or a method of mixing transparent fine particles. It can be obtained by forming a. The fine particles used to form the fine non-uniform structure are transparent fine particles having an average particle diameter of 0.5 to 50 μm, and the fine particles are silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide or antimony oxide. inorganic fine particles that may be conductive, such as (antinomy oxide), and organic fine particles made of a crosslinked polymer or an uncrosslinked polymer. The amount of the fine particles used to form the fine non-uniform surface structure with respect to the weight 100 of the transparent resin forming the fine non-uniform surface structure is generally 2 to 50 by weight, preferably 5 to 25 by weight. The anti-glare layer may also function as a diffusion layer for enlarging the visual angle by diffusing light transmitted by the polarizing plate.

Incidentally, the anti-reflection layer, anti-sticking layer, diffusion layer and anti-glare layer may be used for the transparent protective film itself, or the layer may be provided as an optical layer irrespective of the transparent protective film.

There is no particular limitation on the treatment of bonding the transparent protective film to the polarizing plate, but the adhesive including vinyl polymer, or at least boric acid or borax, glutaraldehyde or melamine, or oxalic acid. It can be carried out using a pressure-sensitive adhesive containing a water-soluble crosslinking agent for alcohol vinyl polymer such as acid). For example, the pressure-sensitive adhesive layer may be added by coating and drying an aqueous solution in the form of a layer, and a catalyst such as an acid and other additives may be mixed to prepare the aqueous solution.

In actual use of the optical film of the present invention, another optical layer may be laminated on the film. No particular limitation is imposed on such optical layers, but examples include reflectors and semitransmissive plates, retardation plates (including 1/2 and quarter wavelength plates) and vision. One or more layers selected from the optical layers used to make the liquid crystal display, such as a compensation film. For example, a reflective polarizer or a semi-transmissive polarizing plate formed by stacking a reflector or a semi-transmissive reflector on a polarizer, or another circular polarizer or circle formed by laminating a phase difference plate on a polarizer. Particular preference is given to a polarizing plate, a wide viewing angle polarizing plate formed by further laminating a visual compensation film on the polarizing plate, and a polarizing plate formed by laminating a brightness increasing film on the polarizing plate.

The reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used in, for example, a liquid crystal display device capable of displaying through reflection of incident light emitted from the visual recognition surface (display surface), whereby a built-in light source such as a backlight can be removed. And it provides the advantage that the low-profile liquid crystal display can be easily produced. The reflective polarizing plate can be produced by an appropriate method such as providing a reflective layer made of metal or the like on one side of the polarizing plate, and a transparent protective layer or the like can be provided if necessary.

As one embodiment of the reflective polarizer, a reflective polarizer including a reflective layer formed by adhering a deposition film of a reflective metal such as foil or aluminum to one side of a transparent protective film having a surface on which a mat is mounted may be formed as needed. In another embodiment of the reflective polarizing plate, a reflective polarizing plate including a reflective layer having a finely uneven structure formed on the transparent protective film may be made, in which case the fine particles may be formed such that the finely uncoated structure is formed on the surface of the reflective layer. Is installed. The reflective layer having a fine uncoated structure emits incident light by scattered reflection, thereby preventing directivity and shiny appearance and controlling nonuniformity due to change in contrast. In addition, the transparent protective film containing the fine particles has an advantage that the incident light and the reflected light is emitted to the passage through the film, thereby further controlling the nonuniformity of the contrast. For example, the reflective layer having a fine charcoal structure reflecting the fine charcoal structure on the surface of the transparent protective film is a method of directly adhering a metal layer to the transparent protective film surface by an appropriate method such as an evaporation process or a plating process, and more specifically, It is formed through a vacuum deposition process, an ion plating process or a sputtering process.

Instead of the method of directly adhering to the transparent protective film of the polarizing plate, the reflector may also be used in the form of a reflective sheet having a reflective layer provided on a suitable film for the transparent film. In addition, the reflective layer is typically made of metal, so that the reflective surface of the layer is made of a transparent protective film, a polarizing plate, in order to prevent degradation of reflectivity due to oxidation, to maintain the initial reflectance for a long time, and to prevent separation of the adhered protective layer. It is preferable to wrap with a back.

In addition, the semi-transmissive polarizing plate may be produced by adopting a semi-transmissive type reflective layer such as a half mirror capable of transmitting light as well as reflecting light by the reflective layer as described above. This semi-transparent transparent polarizing reflector is usually installed behind the liquid crystal cell, for example, in a relatively bright condition to reflect the incident light emitted from the visual recognition surface (display surface) when using the liquid crystal display device to display an image, and relatively dark conditions In the present invention, a liquid crystal display of a type for displaying an image may be formed using a built-in light source such as a backlight installed behind a translucent polarizer. In other words, the semi-transmissive polarizing plate can be used for the production of liquid crystal displays of the type that can be saved using, for example, a light source such as a backlight in bright conditions and can be displayed using a built-in light source in relatively bright conditions. useful. Hereinafter, a circular or elliptical polarized plate in which the reduction plate is further laminated on the polarizing plate will be described. When the linearly polarized light is converted into circular or elliptical polarized light, the circular or elliptical polarized light is converted into linear polarized light or the polarization direction is changed, and a retardation plate is used. A quarter wave plate (also called a λ / 4 plate) is used, with a phase difference plate being used to convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light. A half wave plate (also called a λ / 2 plate) is typically used to change the polarization direction of linearly polarized light.

For example, when compensating (preventing) coloration due to birefringence (coloring in blue or yellow) in a liquid crystal layer of a super twisted nematic (STN) type liquid crystal display or when displaying black and white without this coloration. , Oval polarizing plate is effectively used. In addition, a controllable polarizing plate having a three-dimensional refractive index is preferable because the polarizing plate can compensate (color) the coloring that occurs when the screen of the liquid crystal display is viewed at an angle. For example, a circularly polarized plate can be effectively used when adjusting the color tone of a screen of a reflective liquid crystal display capable of coloring an image and the plate also has an anti-reflection function.

Embodiments of retardation plates include birefringent plates that shorten or biaxially draw a polymer material, a liquid crystal polymer alignment film, and an oriented liquid crystal polymer coating supported by the film. The drawing process can be processed by, for example, a rolling draw method, a long-gap follow drawing method, a tenter drawing method, and a tubular drawing method. The draw rate is usually 1.1 to 3 for uniaxial draw. The thickness of the retardation plate is not particularly limited, but is usually 10 to 200 m, preferably 20 to 100 m.

Examples of polymeric materials include polyvinyl alcohol, polyvinyl butyral, polymethylvinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, poly Alirate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyphenylene sulfide, polyphenylene oxide, polyallyl sulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyolefin, norbornene (norbornene) structures, polyvinyl chlorides, cellulose polymers, various CO- or terpolymers of binary or ternary combinations of monomers constituting the homopolymer, fusion copolymers, two or more of the above materials Mixtures. This polymer material may be formed of a material oriented by drawing or the like.

Embodiments of liquid crystal polymers include various types of polymers having a main chain or side chain that combines linear atom groups into polymers to impart liquid crystal alignment (mesagen), so that the polymers are each of the main-chain type or It is called side-chain type liquid crystal polymer. Main-chain-type mesomorphic polymers include polyester type mesomorphic polymers, discotic polymers, and mesogenic groups in nematic orientation, and cholesteric polymers that bind to spaces that provide flexibility. Embodiments of side chained mesomorphic polymers contain polysiloxanes, polyacrylates, polymethacrylates and polymalonates in their respective main chain structures, and through spaces made of atomic groups bonded to side chains. It further has a mesogen moiety comprising a para-substituted cyclic compound unit providing a nematic orientation. This liquid crystal polymer is used in a state in which each mesomorphic polymer solution is spread over a surface of an oriented and heat treated substrate such as a polyalcohol vinyl film formed on a friction surface of thin polyamide or a silicon dioxide formed by oblique evaporation or a glass film.

The retardation plate can be appropriately adjusted and decelerated depending on the purpose of use, more specifically for the purpose of compensating visual angles due to coloring and birefringence of the plates and liquid crystal layers of various wavelengths. Also, two or more retardation plates can be stacked on top of each other's layers, whereby optical properties including deceleration can be adjusted.

The elliptical polarizer or the reflective elliptical polarizer is a laminate structure in which a retardation plate and a polarizer or a reflective polarizer are appropriately combined. The elliptical polarizing plate may be formed by independently stacking the (reflective) polarizing plate and the retardation plate in sequence during the production of the liquid crystal display. However, as described above, an optical film such as an elliptical polarizing plate is first made, which is excellent in quality consistency, lamination workability and the like and improves the efficiency of production of the liquid crystal display.

The viewing angle compensating film enlarges the viewing angle so that the image can be viewed with relatively high sharpness even when viewed in an oblique direction rather than perpendicular to the screen. This viewing angle compensation film includes, for example, a retardation plate and an alignment film, for example, a liquid crystal polymer or an alignment layer, for example, a liquid crystal polymer supported by a transmissive substrate. When a birefringent polymer film by uniaxial drawing in its planar direction is used as a conventional retardation plate, the retardation plate used as a viewing angle compensation film is, for example, a birefringent polymer film by biaxial drawing in its planar direction And a film drawn in two directions, such as a polymer film and a diagonally oriented film, which are not only uniaxially drawn in their planar direction but also in their thickness direction and thereby are birefringent at a refractive index controlled in the thickness direction. The diagonally oriented film includes a polymer film and a diagonally oriented liquid crystal polymer alignment film which are bonded to a heat shrinkable film and then drawn or / and shrink treated under the action of shrinkage force by heating. The polymer used as the material of the retardation plate includes the same polymer as in the above description of the retardation plate, and prevents coloring caused by the change of the viewing angle due to the deceleration by the liquid crystal cell, and the extension of the viewing angle for good visual recognition. Suitable polymers are used.

Also, for example, an optically anisotropic layer of oriented liquid crystal polymer layers supported by a triacetylcellulose film, more specifically a diagonally oriented discotic liquid crystal polymer layer, to obtain a wide viewing angle for good visual recognition. It is advantageous to use. The polarizing plate in which a brightness enhancement film is laminated on the polarizing plate is installed on the rear side of the liquid crystal cell. This brightness increasing film reflects linear light polarized in a specific polarization direction or circularly polarized light in a specific direction, and transmits other light when natural light emitted from the back light and back reflection of the liquid crystal display is incident on the film surface. Characteristics. When light from a light source such as a backlight enters a polarizing plate having a brightness increasing film laminated to the polarizing plate, the polarizing plate passes through the light in a specifically polarized state and at the same time exits the specifically polarized state without transmission and reflects the light. The light reflected by the brightness increasing film is further reversed by a reflecting film or the like disposed on the rear side and is incident again to the brightness increasing film, so that all or part of the incident light passes in a specifically polarized state, thereby allowing the brightness increasing film to pass through. It not only affects the amount of light passing through, but also affects the supply of polarized light which is less likely to be absorbed by the polarizing plate. As a result, it is possible to increase the amount of light used for the display of the liquid crystal image, thereby increasing the brightness. In other words, when light is incident through a polarizing plate that is not provided with a brightness increasing film on the rear side of the liquid crystal cell by using a backlight or the like, most of the light polarized in a direction inconsistent with the polarization axis of the polarizing plate is absorbed by the polarizing plate, and the polarizing plate is almost It does not penetrate. More specifically, depending on the characteristics of the polarizing plate used, about 50% of the light is absorbed by the polarizing plate, and the amount of light used for the liquid crystal image, etc. is greatly reduced so that the image is displayed black. The brightness increasing plate avoids incidence of light in the direction for absorption of the light of the polarizing plate, so that the light is once reflected by the brightness increasing film and then reversed, for example, by the reflective layer provided on the rear side and the brightness Is reincident to the increasing film. By repeating this process, the brightness increasing film transmits light that is polarized in the upward direction to pass through the polarizer during reflection and to be reversed between the two members, resulting in supplying light to the polarizer. Therefore, the light from the backlight or the like is effective for displaying an image in the liquid crystal display device and can make this display screen bright.

In addition, a diffusing plate may be provided between the brightness increasing film and the reflective layer. The light reflected and polarized by the brightness increasing film is transmitted to the reflective layer or the like, and when the light passes through the diffuser plate, the light is uniformly emitted and at the same time, the polarized state of the light is decomposed. As a result, the light becomes unpolarized. In other words, this light is restored to the state of natural light. This light in an unpolarized or natural light state is transmitted to a reflective layer or the like, and then is reflected through the reflective layer or the like and passes through the diffuser plate to further enter the brightness increasing film. This process is repeated. By providing a diffuser plate for recovering light in the natural light state, the nonuniformity of the brightness of the display screen is reduced while maintaining the brightness of the display screen, thus obtaining a uniform and bright screen. More specifically, the reflection of the initial incident light suitably increases the number of times repeated by providing the diffuser plate which preserves in the natural light state, and the effect can be combined with the diverging function of the diffuser plate to make a uniform and bright display screen.

Embodiments of brightness enhancing films usable in the present invention are those that transmit light polarized along a predetermined polarization axis and pass different light, such as multilayer thin films of dielectrics or multilayer stacks of thin films of different refractive index anistropy. A film having a property of reflecting polarized light in one of the right or left hand rotation directions, such as a film having a characteristic of reflecting and a cholesteric liquid crystalline polymer alignment film and an oriented liquid crystal layer supported by the film substrate, and transmitting a different light. Include.

Thus, when using the above-described brightness enhancement film of the type that transmits linearly polarized light along a predetermined polarization axis, the light transmitted thereby is incident on the polarizing plate with their polarization axes aligned, thereby absorbing the polarizing plate. The loss can be controlled and effectively transmitted. In addition, when using a brightness enhancement film of a type that transmits circularly polarized light such as a cholesteric liquid crystal polarizing plate, the transmitted light may be incident on the polarizing plate in its original state, but the control of absorption loss In view of the above, it is preferable that the circularly polarized light is linearly polarized through the retardation plate to be incident on the polarizing plate. Incidentally, by using a quarter wavelength plate as the phase difference plate, circularly polarized light can be converted into linearly polarized light.

Like the visible light region, a retardation plate functioning as a quarter wave plate having a wide wavelength range includes a retardation plate functioning as a quarter wave plate of monochromatic light having a wavelength of 550 nm, and a phase difference plate functioning as a half wave plate. It can be obtained by superimposing on retardation plates having the same different retardation characteristics. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancing film may be one retardation layer or a layer including two or more retardation layers.

In addition, a cholesteric liquid crystal layer reflecting circularly polarized light of a wide wavelength range, such as a visible light region, may be formed by stacking two or three combination layers of different wavelengths of reflected light in order to stack different layers on one layer. And in this way transmission of circularly polarized light in a wide wavelength range can be achieved.

In addition, the polarizing plate may be a laminate of a polarizing plate such as the above-described split type polarizing plate and two or more optical layers. Accordingly, the polarizing plate may be a semi-transparent elliptical polarizing plate formed by combining each of the above-mentioned reflective polarizing plate or translucent polarizing plate with a reflective elliptical polarizing plate or a retardation plate.

The optical film having the above-described optical layer on the polarizing plate in the stacked state is formed by independently laminating the optical layers on the polarizing plate in the course of manufacturing a liquid crystal display device or the like. However, the optical layer / polarizing plate before lamination with the optical film is superior in stability of quality, assembly workability, and the like, and has an advantage of improving the manufacturing process of the liquid crystal display device. In the lamination operation, an appropriate adhesion technique such as an adhesive layer can be employed. When adhering the polarizing plates to other optical layers, the optical angle between them can be made to form an appropriate placement angle according to the intended phase difference characteristics.

The adhesive optical film of the present invention is advantageous for the formation of an image display device including a liquid crystal display (LCD), an electroluminescent display (ELD), a plasma display panel (PDP) and a field emission display (FED). 4A illustrates an embodiment in which a liquid crystal display device is formed by adhering the adhesive optical films shown in FIGS. 1A and 2A to both sides of the liquid crystal cell 9. FIG. 4B shows an embodiment of an electroluminescent display formed by adhering the adhesive optical film shown in FIG. 3A to one side of a luminous body 10 (organic electroluminescent panel) to be described below.

The present adhesive optical film is advantageous for producing various kinds of devices including liquid crystal display devices. Formation of the liquid crystal display device can be performed by a conventional method. Typically, this liquid crystal display device can be formed by assembling a liquid crystal cell, an adhesive optical film, and, if necessary, other components including an illumination system, which is then provided with a drive circuit. The present invention is not particularly limited except for using the polarizing plate and the optical film according to the present invention, and the rest follows a conventional method. Any kind of liquid crystal cell used in the present invention may be used, but in particular, a TN type, an STN type, or a π type is used.

A liquid crystal display using a backlight or a reflector may be formed as a liquid crystal display or an illumination system in which the adhesive optical film is disposed on one side or both sides of the liquid crystal cell. In this case, the polarizing plate or the optical film according to the present invention may be disposed on one side or both sides of the liquid crystal cell. When polarizing plates or optical films are placed on both sides, they may be the same or different from each other. When forming a liquid crystal display device, a diffusion plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, and the like may be appropriately used. A combination of one or more layers selected in the component may further be placed in the appropriate location.

Hereinafter, an organic electroluminescent device (organic EL display device) will be described. Typically, a light emitting body (organic electroluminescent panel) is formed of an organic EL display by successively laminating a transparent electrode, an organic light emitting layer, and a metal electrode on a transparent substrate. At this time, the organic light emitting layer is a laminate of various organic thin films, a hole injection layer made of a triphenylamine derivative or the like, and an electron made of a light emitting layer made of a fluorescent organic solid such as anthracene, an emitting layer and a perylene derivative, and the like. There is a known structure having various combinations, such as a laminate of injection layers and a laminate of a hole injection layer, a light emitting layer and an electron injection layer as described above.

In the organic EL display device, a voltage is applied between the transparent electrode and the metal electrode so that holes and electrons are injected into the organic emission layer to generate energy by recombination between the two, and this energy excites the fluorescent material. The fluorescent material emits light when it returns to the ground state. The recombination mechanism that occurs in the middle of the process is similar to that of a conventional diode. Similarly, the current and intensity of the light emitted exhibits strong nonlinearity in rectification with respect to the applied voltage.

In an organic EL display, at least one electrode must be transparent in order to emit light in the organic light emitting layer, and thus a transparent electrode formed of a transparent conductor such as an indium tin layer (ITO) is usually used as a positive electrode. In addition, metal electrodes such as Mg-Ag or Al-Li are commonly used because it is important to use a substrate having a small work function, such as a negative electrode, in order to improve luminous efficiency by easy injection of the electrode. .

In the organic EL display device having the above structure, the organic light emitting layer is a very thin film having a thickness of 10 nm. Therefore, almost all light passes through the organic light emitting layer in the case of the transparent electrode. As a result, when the display is in a state of stopping light emission, light incident from the surface of the transparent substrate passes through the transparent electrode and the organic light emitting layer, is reflected by the metal electrode and returns to the side of the surface of the transparent substrate. Thus, the screen of the organic EL display looks like a mirror surface when viewed from the outside.

In an organic EL display device comprising an organic electroluminescent panel provided with a transparent electrode on the surface of the organic light emitting layer capable of emitting light by application of a voltage of the organic light emitting layer and provided with a metal electrode on the rear side, the polarizing plate is placed on the surface of the transparent electrode. It is possible to arrange, and a retardation film can also be arranged between the transparent electrode and the polarizing plate.

The retardation film and the polarizing plate function to polarize light incident from the outside and reflect it from the metal electrode. This polarization function has the effect of making it impossible to visually recognize the mirror-like surface of the metal electrode from the outside. When the retardation film is made especially of a quarter wave plate, and the angle formed by the polarization direction of the polarizing plate and the retardation film corresponds to [pi] / 4, the mirror-like surface of the metal electrode is completely shielded.

In other words, linearly polarized components of external light incident on the organic EL display can pass through the action of the polarizing plate. Although the use of a retardation film typically converts linearly polarized light into elliptical polarized light, the quarter wave plate is used as a slow film and the angle formed by the polarization direction of the polarizer and the slow film corresponds to π / 4. In the case of the linearly polarized light may be converted into a circularly polarized light.

The circularly polarized light passes through the transparent substrate, the transparent electrode, and the organic thin film, is reflected from the metal electrode, and again passes through the organic thin film, the transparent electrode, and the transparent substrate, and the circularly polarized light is linearly passed through the phase difference film. Converted to polarized light. And since this linearly polarized light is perpendicular to the polarization direction of the polarizing plate, it cannot pass through the polarizing plate. As a result, the specular surface of the metal electrode can be completely shielded.

As described above, the present invention solves a problem caused by forming a predetermined portion inside the edge line of the optical film of the pressure-sensitive adhesive layer included in the pressure-sensitive adhesive optical film, such as pressure-sensitive adhesive chip problems, pressure-sensitive adhesive contamination problems.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention should not be construed as being limited to these Examples. In addition, all parts and percentages in each example are by weight.

<Example 1>

(Production of Acrylic Polymer)

A detachable flask equipped with thermometer, stirrer, reflux condenser and nitrogen gas introduction tube contains 30 parts of 97 parts butyl acrylate, 3 parts acrylic acid, 0.2 parts azobisisobutyronitrile and 30% solids. The required amount of ethyl acetate was prepared to adjust to the furnace, after which nitrogen was introduced into the flask and subjected to nitrogen substitution for about 1 hour with stirring of the components in the flask. Thereafter, the reaction proceeded for 7 hours while heating the flask at 60 ° C. to obtain an acrylic polymer having a weight average molecular weight (Mw) of 1,100,000.

(Preparation of Adhesive Composition)

The pressure-sensitive adhesive composition (solution form) is an acrylic polymer (100 parts by weight based on solids) prepared by the method described above, 10 parts by weight of butyl acrylate (BA) oligomer (Mw = 3,000), 0.8 parts by weight of trimethylolpropane as an isocyanate-based crosslinking agent. It is prepared by mixing with toly lenidisocyanate (Coronate L, product of Nippon Polyurethane Industry Co., Ltd.) and 0.1 parts by weight of silane binder (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd).

(Production of Adhesive Optical Film)

An 80 μm thick polyvinyl alcohol film is drawn in five layers in an aqueous iodine solution and then dried. The triacetyl cellulose film was bonded to both sides of the thus-drawn film with an adhesive to form a polarizing plate. The polarizer plate thus made is stamped into a size of 11 inches by a Thomson blade. Then, the coating of the pressure-sensitive adhesive solution prepared by the above-described method is coated on a 35 탆 thick polyethylene terephthalate-based release film, so that the coating after drying has a thickness of 25 탆 and the edge of the dried coating is 300 from each edge of the polarizing plate. With a size of 11 inches to be placed inside the μm, the polarizer was laminated on the pressure-sensitive adhesive coating thus formed and then dried at about 100 ° C. for 4 minutes. Thus, a pressure-sensitive adhesive optical film (adhesive polarizing plate) having a pressure-sensitive adhesive layer formed in the manner described above is obtained.

<Example 2>

Prepared in Example 1 on a 38 μm thick polyethylene terephthalate-based release film, on a polarizing plate sized 11 inches by a Thompson blade as used in Example 1 (to make another adhesive optical film) A pressure-sensitive adhesive release film made by forming a coating of the same pressure-sensitive adhesive solution was laminated to cover an entire area of 11 inches and a dry thickness of 25 μm was obtained. The coating was then dried at about 100 ° C. for 4 minutes to obtain an adhesive layer (loss modulus ( loss elasticity modulus): 8.0 × 10 ⁴ Pa (25 ℃) to obtain a pressure-sensitive adhesive polarizer. The 50 adhesive polarizer plates thus produced were laminated and tightened at the top and bottom by a vise-shaped jig while controlling the pressure so that the adhesive flowed out of the edge. In the pressed state, the pressure-sensitive adhesive layer was cut together with the optical film at a position of 1.0 mm inward from each optical film edge by the rotatable blade. Thereafter, the pressure was released from the laminated sheets. As a result, an adhesive polarizing plate formed at 150 µm (longest) inward from each edge of each edge optical film of the pressure-sensitive adhesive layer was obtained.

<Example 3>

Prepared in Example 1 on a 38 μm thick polyethylene terephthalate-based release film, on a polarizing plate sized 11 inches by a Thompson blade as used in Example 1 (to make another adhesive optical film) A pressure-sensitive adhesive release film made by forming a coating of the same pressure-sensitive adhesive solution was laminated to cover an entire area of 11 inches and a dry thickness of 40 μm was obtained. The coating was then dried at about 100 ° C. for 4 minutes to obtain a pressure-sensitive adhesive layer (loss modulus ( loss elasticity modulus): 1.1 × 10 ³ Pa (25 ℃) to obtain a pressure-sensitive adhesive polarizer. The 50 adhesive polarizer plates thus produced were laminated and tightened at the top and bottom by a vise-shaped jig while controlling the pressure so that the adhesive flowed out of the edge. In the pressed state, the pressure-sensitive adhesive layer which flowed out of the optical film was cut by the rotatable blade. Thereafter, the pressure was released from the laminated sheets. As a result, an adhesive polarizing plate formed at 150 µm (longest) inward from each edge of each edge optical film of the pressure-sensitive adhesive layer was obtained.

<Example 4>

An adhesive retardation plate in which each edge of the pressure-sensitive adhesive layer was formed at 150 µm inward from each edge of the optical film was manufactured in the same manner as in Example 3, except that the norbornene film (ARTON, manufactured by JSR) was 1.5 in the MD direction. The only difference is that the retardation plate formed by uniaxial drawing is used instead of the polarizing plate.

<Example 5>

In a detachable flask, 100 parts by weight of 2-ethylhexyl acrylate and 1 part by weight of a photopolymerization initiator (Irgacure 184, product of Ciba Specialty Chemicals) were introduced, followed by the addition of a metal halide with stirring in a nitrogen gas stream of the mercury lamp. UV light was irradiated to prepare an adhesive composition (solution) having a polymerization rate of 10%. A coating of this composition was formed on a 125 μm-thick polyethylene terephthalate-based release film to have a dry thickness of 1 mm, and then the UV light was irradiated onto the coating until the residual monomer content was 5% by weight or less. The residual monomer was then removed from the cured coating by drying at 150 ° C. for 30 minutes with a hot air dryer. Thereafter, in the same manner as in Example 3, a polarizing plate was laminated on the thus treated and cured coating, and an adhesive polarizing plate was formed in which each edge of the pressure-sensitive adhesive layer was formed 150 µm (longest) inward from each edge of the optical film. lost. In this case, the loss modulus of the pressure-sensitive adhesive layer was 2.1 x 10 ⁴ Pa.

<Example 6>

An adhesive polarizing plate in which each edge of the pressure-sensitive adhesive layer was formed at 150 μm (longest) inward from each edge of the optical film was prepared in the same manner as in Example 2, except that in Example 1 (to prepare an adhesive composition) The same amount of butyl acrylate (BA) oligomer (Mw = 3,000) as used was increased to 20 parts by weight and the loss modulus of the pressure-sensitive adhesive layer was 4.0 × 10 ⁴ Pa (25 ° C.).

<Example 7>

An adhesive polarizing plate in which each edge of the pressure-sensitive adhesive layer was formed at 150 μm (longest) inward from each edge of the optical film was prepared in the same manner as in Example 2, except that in Example 1 (to prepare an adhesive composition) The same amount of butyl acrylate (BA) oligomer (Mw = 3,000) as used was increased to 100 parts by weight and the loss modulus of the pressure-sensitive adhesive layer was 7.5 × 10 ³ Pa (25 ° C.).

<Example 8>

A pressure-sensitive adhesive polarizing plate in which each edge of the pressure-sensitive adhesive layer was formed at 150 μm (longest) inward from each edge of the optical film was prepared in the same manner as in Example 2, except that in Example 1 (for preparing the adhesive composition) The same amount of butyl acrylate (BA) oligomer (Mw = 3,000) as used was increased to 200 parts by weight and the loss modulus of the pressure-sensitive adhesive layer was 1.1 × 10 ³ Pa (25 ° C.).

Example 9

An adhesive polarizing plate in which each edge of the pressure-sensitive adhesive layer was formed at 55 μm (longest) inward from each edge of the optical film was prepared in the same manner as in Example 2, except that the amount of the pressure-sensitive adhesive layer was reduced.

<Example 10>

An adhesive polarizing plate in which each edge of the pressure-sensitive adhesive layer was formed at 100 μm (longest) inward from each edge of the optical film was prepared in the same manner as in Example 2, except that the amount of the pressure-sensitive adhesive layer was reduced.

Comparative Example 1

Prepared in Example 1 on a 35 μm thick polyethylene terephthalate-based release film on a polarizing plate sized to 11 inches by a Thompson blade as used in Example 1 (to make another adhesive optical film) A pressure-sensitive adhesive release film made by forming a coating of the same pressure-sensitive adhesive solution was laminated to cover an entire area of 11 inches to obtain a dry thickness of 25 μm, and then the laminate was dried at about 100 ° C. for 4 minutes to obtain a pressure-sensitive adhesive layer. A polarizing plate was made.

<Evaluation>

(Side adhesion)

The pressure-sensitive adhesive polarizing plate made in the above manner is examined for the feeling of adhesion by the touch of the finger on its side.

(Adhesive chip)

50 adhesive polarizers prepared in each of Examples and Comparative Examples were laminated, packaged, and transported for about 10 hours in a loading box of a truck. Then, each package was opened and the number of sheets in which the adhesive chip of 350 micrometers or more generate | occur | produced was counted.

The evaluation results are shown in Table 1.

      Tack on the side         Adhesive chip         Example 1           none           0/50         Example 2           none           0/50         Example 3           none           0/50         Example 4           none           0/50         Example 5           none           0/50         Example 6           none           0/50         Example 7           none           0/50         Example 8           none           0/50         Example 9           none           0/50         Example 10           none           0/50         Comparative Example 1           has exist           17/50

As a result of the results shown in Table 1, the pressure-sensitive adhesive optical film in which each pressure-sensitive adhesive layer was disposed inside the edge line of the optical film had no adhesiveness on the surface of the film, and no pressure-sensitive adhesive chip occurred.

Although the present invention has been described in detail with reference to specific embodiments, various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

The present invention is based on Japanese Patent Application No. 2002-312699, filed October 28, 2002 and Japanese Patent Application No. 2003-317383, filed September 9, 2003, the contents of which are incorporated by reference.

1A and 1B are schematic cross-sectional views of a pressure-sensitive adhesive optical film according to the present invention.

2A to 2D are schematic views showing examples of cross-sectional shapes of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive optical film according to the present invention.

3A and 3B are schematic views showing examples of cross-sectional shapes of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive optical film of the present invention having two or more pressure-sensitive adhesive layers.

FIG. 4A is an example of an image display apparatus made using the pressure-sensitive adhesive optical film shown in FIGS. 1A and 2A.

FIG. 4B is an example of the image display apparatus made using the said adhesive optical film shown in FIG. 3A.

Brief description of symbols for the main parts of the drawings

1: Optical film 2: Adhesive layer

3: any one of a release film, an optical layer, an optical film, and an adhesive layer

4: adhesive optical film

Claims (14)

delete delete delete The first optical film and In the adhesive optical film containing the 1st adhesive layer laminated | stacked on at least one of this 1st optical film, Furthermore, one or more layers selected from a release film and a 2nd optical film are provided in the 2nd surface on the opposite side to the 1st surface in which the said 1st optical film of the said 1st adhesive layer is provided, At least a portion of an edge of the first pressure sensitive adhesive layer is an edge line of the first optical film that intersects the surface of the first optical film that faces the first surface of the pressure sensitive adhesive layer, and the pressure sensitive adhesive layer An inner edge located inside the edge line of the at least one layer selected from the release film and the second optical film that intersects the surface of the at least one layer selected from the release film and the second optical film opposite the second surface. edge), A portion in the cross section of the inner edge extends to the edge of the first optical film or near the edge of one or more layers selected from the release film and the second optical film, And the inner edge is a concave edge. The first optical film and In the adhesive optical film containing the 1st adhesive layer laminated | stacked on at least one of this 1st optical film, Furthermore, one or more layers selected from a release film and a 2nd optical film are provided in the 2nd surface on the opposite side to the 1st surface in which the said 1st optical film of the said 1st adhesive layer is provided, At least a portion of an edge of the first pressure sensitive adhesive layer is an edge line of the first optical film that intersects the surface of the first optical film that faces the first surface of the pressure sensitive adhesive layer, and the pressure sensitive adhesive layer An inner edge located inside the edge line of the at least one layer selected from the release film and the second optical film that intersects the surface of the at least one layer selected from the release film and the second optical film opposite the second surface. edge), A portion in the cross section of the inner edge extends to the edge of the first optical film or near the edge of one or more layers selected from the release film and the second optical film, And the inner edge is a convex edge. delete delete The method according to claim 4 or 5, Adhesive edge optical film, characterized in that the maximum value of the distance between the edge of the first optical film, or the edge of the at least one layer selected from the release film and the second optical film and the inner edge is 10 to 300 ㎛. . The method according to claim 4 or 5, Adhesive optical film used for an image display apparatus. The method according to claim 4 or 5, And a minimum value of a distance between an edge of the first optical film or an edge of one or more layers selected from the release film and the second optical film and the inner edge is 5 to 50 μm. In the manufacturing method of the adhesive optical film of Claim 4 or 5, Forming an adhesive layer on the optical film; Pressing the pressure sensitive adhesive layer from both sides to drain a portion of the pressure sensitive adhesive layer from the side edges of the optical film; Cutting or cutting the side surface of the pressure-sensitive adhesive layer; And Method of producing a pressure-sensitive adhesive optical film comprising the step of releasing the pressure on the pressure-sensitive adhesive layer. The method of claim 11, The pressure-sensitive adhesive layer, the pressure-sensitive adhesive optical film, characterized in that it comprises an adhesive having a storage modulus (storage modulus) of 1.0 x 10 ⁴ to 1.0 x 10 ⁷ Pa at 25 ℃ determined from the dynamic viscoelasticity . The method of claim 11, The step of releasing the pressure on the pressure-sensitive adhesive layer, the method of manufacturing a pressure-sensitive adhesive optical film comprising pulling the pressure-sensitive adhesive layer toward the outside in the thickness direction of the pressure-sensitive adhesive layer. The method of claim 11, In the step of cutting or cutting the side of the pressure-sensitive adhesive layer, the optical film is a method of manufacturing a pressure-sensitive adhesive optical film, characterized in that the cutting or cutting with the pressure-sensitive adhesive layer.

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